Multi-functional middle distillate additive



United States Patent ()fifice 3,042,505 Fatented July 3, 1062 3,042,505MULTI-FUNCTIONAL MIDDLE DISTILLATE ADDITKVE William C. Hollyday, Jr.,Plainfield, N.J., assignor to Esso Research and Engineering Company, acorpora- -tion of Delaware No Drawing. Filed Oct. 18, 1960, Ser. No.63,259 5 Claims. (Cl. 44--62) The present invention is concerned with animproved multi-functional additive suitable for addition to middledistillates which will give these middle distillates improved pours,higher stabilities, higher detergences and also improve the sludgecharacteristics. More particularly, the present invention relates to thepreparation of improved low cold test hydrocarbon fuels, especially inheating oils and diesel fuels, kerosene, aviation turbojet fuels, andother fuels that are subject to low temperatures. In accordance with thepresent invention, an improved class of pour depressants is utilizedwith middle distillates which comprise condensation products of anacylated polystyrene with various arnino compounds.

With the increase in the use of hydrocarbon fuels of all kinds, aserious problem has arisen in areas frequently subject to lowtemperatures in the cold test characteristics of fuels. Particularly,serious problems have been encountered by heating oils and diesel andjet fuels that have too high a pour point, resulting either indistributional or operating difiiculties or both. For example, thedistribution of heating oilsby pumping or syphoning is rendereddifficult or impossible at temperatures around or below the pour pointof the oil. Furthermore, the flow of the oil at such temperaturesthrough the filters cannot be maintained, leading to the failure of theequipment to operate.

It is well known to add pour depressants to lubricating oils to lowerthe pour point. These lube oil additives, mostly high molecular weightorganic compositions formed by alkylation of benzene or naphthalene orderivatives thereof or by polymerization of lower molecular weightmethacrylates, or by condensation polymerization of various kinds, arenot satisfactory in service with middle distillate and lighter fuels.Poor performance of these additives might possibly result from thestructural differences between waxes occurring in lubricating oils andso-called middle distillates.

A wide variety of compounds have been found to be effective as pourpoint depressants for lubricating oil. Among the best known areParaflow, Santopour and Acryloid and their modifications. They areprepared either by condensing aromatic compounds with long chainparaflins, such as wax, or by condensing olefinic esters. It isgenerally considered that these pour depressants are effective in thatin cooling an additive-containing oil, the hydrocarbon chain of theadditive becomes incorporated into the crystal lattice of the separatedwax, while the other part of the pour depressant molecule prevents thecrystals from adhering together to form a gel strutcure. The failure ofthese additives to be effective in middle distillates may at least inpart be due to the basic diiference in the composition between the waxin lubricating oils and that in middle distillate fuels.

It is, therefore, one object of the present invention to set forth animproved pour depressant for middle distillate and lighter fuels. Theboiling ranges of these oils are generally about 250 to 750 F. Anotherobject of the present invention is to use a multi-functional middledistillate additive for the improving of stabilization, the detergency,and the sludge characteristics of these fuels.

The petroleum distillate fuels in which the additive materials of theinvention are employed consist of a major proportion, at least 95% ofliquid hydrocarbons boiling at temperatures between about F. and about750 F. These fuels include gasolines such as aviation, marine andautomotive or motor gasolines, aviation turbojet fuels such as lP-l,JP-4 and JP'5 fuels, and diesel fuels such as marine, stationary andautomotive diesel engine fuels.

Aviation turbo-jet fuel consists of at least of a mixture of volatilehydrocarbons. It is defined by US. Military Specifications MIL-F-5616and MIL-F-5624C. its volatility is such that its end point does notexceed 572 F. Its viscosity is between 0.5 and 1.5 centistokes at F.

Diesel fuels as referred to in connection with the invention consist ofat least 95 of a mixture of hydrocarbons boiling between 250 F. and 750F. either by ASTM Method D 8656 when their end points do not exceed 600F. or by ASTM Method D-l58-54. Diesel fuels are defined by ASTMSpecification D975-53T and fall into Grades 1D, 2D and 4D, in all ofwhich the additive materials of the invention may be used. They haveviscosities between 1.4 and 26.4 centistokes.

The liquid fuels in which the additive materials may be incorporatedthus comprise at least 95 by weight of a mixture of hydrocarbons havinga boiling range between the limits of 75 F. and 750 F. and a viscositybetween the limits of 0.264 and 26.4 centistokes at 100 F.

As pointed out heretofore, the new polymeric materials of the presentinvention giving improved pour, stabilization, detergency, and sludgedispersion characteristics to a middle distillate fuel, are prepared bythe condensation of acylated polystyrene with amino compounds.

The acylated polystyrene compounds are prepared with certain fatty acidchlorides of critical composition and are active pour depressants formiddle distillates. The acylates of interest have the followingstructure:

is defined according to the contributory number table and R is normallya straight chain alkyl group of about C to C and X is a number from 3 to20.

In general, the method of acylation may vary appreciably. The methodswhich are disclosed in US. Patent No. 2,703,817, entitled Process forthe Preparation of Lubricating Oil Additives," Inventor: George E.Serniuk, and in US. Patent No. 2,500,082, entitled Acylated Derivativesof High Molecular Weight Copolymers, Inventors: Eugene Lieber andWilliam H. Smyers, may be utilized.

Broadly, the method of acylation comprises dissolving the polystyrene ina suitable solvent, such as chlorobenzene, o-dichlorobenzene, or tetrachloro-ethylene and adding to the solution the equimolar carboxylic acidchlo ride/ aluminum chloride complex at temperatures of 30 to 70 C.(preferably, 40 to 60 C.), with provision for 70 carrying away theevolved hydrogen chloride.

After all the acid chloride/ aluminum chloride complex has been added(one mole per mole of phenyl groups in aluminum chloride.

the polystyrene, plus a slight excess) and hydrogen chlo ride evolutionhas stopped, the catalyst is destroyed with Water or alcohol, theacylate is taken up in a suitable solvent, such as heptane or keroseneand washed with Water and alkaline solutions. The resinous product maybe isolated as the pure material by evaporating all solvents, or it maybe used in solution for making blends in middle distillates.

For obtaining the superior acylated polystyrene, it is desired that thepolystyrene starting material have an intrinsic viscosity within a rangeof about 0.2 to 2.0, preferably 0.8 to 1.5. These viscosities correspondto molecular weights within a range of from about 10,000 to 75,000,preferably 30,000 to 60,000 Staudinger (if the constant for isobutylenepolymers is assumed to apply). Since the amounts of the other reactantsare based on the weight of the polystyrene, the amount of polystyreneused will depend upon restrictions such as equipment capacity, etc. Thecryoscopic molecular weight after acylation was about 700 to 5,000; theintrinsic viscosity about 0.05 to 0.5. The 700 molecular weightcomprises, in essence, a trimer containing three acylated phenyl groups,Whereas, the 5,000 molecular weight comprises, in essence, about 18acylated phenyl groups, on the average, per polymer molecule.

The acylating agent chosen for the preparation of the acylatedpolystyrene of this invention will be aliphatic in nature and willpreferably contain from 8 to 16 carbon atoms in a straight chain.Although C C C C and C acid chlorides are used in the examplesspecifically detailing the instant invention, any straight chain acidchlorides having the above requirements may be used. It is preferredthat equimolar quantities of polystyrene and the acylating agent beused, however, from 0.80 to 1.20 mols "of acylating agent per molequivalent of polystyrene is operable. A large excess of acylating agentdoes not harm, but it does not react and so is wasted. As mentioned,suitable acyl groups include acetyl, butyryl, capryl, decanoyl,do-decanoy-l, tetra-decanoyl, hexadecanoyl stearoyl and benzoyl.

These acylates are condensed with primary and secondary aliphatic andaromatic amines such as methyl amine, n-propyl amine, t-butyl amine,n-octyl amine, ndo-decyl amine, n-octadecyl amine, aniline, N-methylaniline, N-ethyl aniline, p-amino phenol, p-methoxy aniline, p-aminophenyl stearate, alpha-naphthylarnine and beta-naphthylamine.

These. compounds may be prepared in the following manner.

EXAMPLE 1 CH=CHg 2) x X XRCOCl/AlCla O Simultaneous polymerization andacylation of polystyrene were carried out by the addition of a solutionof 1.00 mole weight (104 g.) of polystyrene in o-dichlorobenzene solventto an acid chloride/ aluminum chloride complex. The complex contained0.35 mole of n-dodecanoyl chloride, 0.35 mole of n-tetra decanoylchloride, 0.35 mole of n-decanoyl chloride and 1.05 moles of anhydrousThe temperature was maintained at 5 to 40 C. during the reaction. Theproduct was recovered by Washing the reaction mixture with alkalinesolutions and evaporating the solvent. The polymeric 'product had anintrinsic viscosity of 0.05 and was ob- "tained in a yield of 96% of thetheoretical, based on the assumption that the product contained one acylgroup per phenyl group.

The acylated polystyrene prepared as described was The temperature wasC. and the catalyst a few pellets of sodium hydroxide. The followingreaction took place:

+ m n H20 o=o-R C 2Hz5N=CR Benzene and water were removed bydistillation. The polymeric product contained 1.99% nitrogen, whichindicates that about two-thirds of the acyl groups reacted with amine.

EXAMPLE 2 Various amounts of the pour depressants of the presentinvention were utilized in distillate fuels. A typical distillate fuelboiling in the range from 250 to 750 F. to which the present additivesmay be added are middle distillate heating oils. These fuels are ofcommercial grade and have typical properties as follows.

The improvements obtained by adding the additives in accordance with thepresent invention are set forth in the following table. All pour pointsquoted hereafter were obtained by ASTM Method D-97-47.

The heating oil from Venezuela crude had a boiling range of 354-624 R,an API gravity of 37.6 and a viscosity of 2.35 cs. at 100 F. The heatingoil from Canada crude had a boiling range of 316 to 685 R, an APIgravity of 35.4, and a viscosity of 2.85 cs. at 100 F.

Table I POUR DEPRESSANT ACTIVITY OF ACYLA'IED POLYSTY- RENE/AMINEOONDENSATE Test Oil Description Wt. percent Po Polymer 1 Point, F

0. 01 5 Heating Oil from Venezuela Crude 8' Ii, 0. 05 15 0. 10 -15 0. 00+10 0. 01 0 Heating Oil from Canada Crude 8' g; :%g 0. 05 35 0. 10 -40 1Acylated polystyrene/amine condensate from Example 1.

EXAMPLE 3 In other tests, the effectiveness of the additives incontrolling sediment were carried out. The results of these runs areshown in the following Table II. The heating oil used had a boilingrange of 382660 R, an API gravity of 35.0 and a viscosity of 3.10 cs. at100 F.

Table II POTENTIAL SEDIMENT TEST Test description: A sample of themiddle distillate (200 ml.) is carefully filtered and then held at 210F. for 16 hours, with exposure to air. During this treatment somesediment develops. This potential sediment is reported in mg. per 100ml. of sample.

Test results:

Pour Potential Heating Oil Tested Point, Sediment,

F. rug/ml.

(A) Mixed Heating Oil (50/50 cracked and 0.45

straight run stocks from Venezuela crude.) (B) Same Heating Oil +0.02Wt. percent product from Example 1 20 0.10

EXAMPLE 4 In further tests, the efiectiveness in the control of filterplugging were carried out with the following results shown in table III.

Table III ACCELERATED FILTER PLUGGING TEST Test results:

Dernerits Liters 01' Heating Oil Sample Tested Filtered Pres. SedimentSediment Overall Drop Appear- Weight (Aver) ance (A) Table II 8. 2 8. 5.0 3. 8 2 8. 3 (B) Table II 12.0 4. 4 4. 0 3. 7 3 4. 0

1 Ranging from 0 to 10.

1 Average demerit multiplied by the factor 12.0/8.2 because only 8.2liters filtered.

3 Equal to demerit obtained with commercial stabilizer.

The amount "of the condensation product. used may vary appreciablydepending upon the particular stock in which it is used. However, thegeneral range is from about 0.001 to 0.5 weight percent, preferably from0.05 to 0.1%.

What is claimed is:

1. A petroleum distillate fuel composition having an improved pour andimproved stability against sedimentation which comprises essentially apetroleum distillate fuel boiling in the range between 250 F. and about750 P. which has been improved with respect to pour point by theincorporation therein of a pour depressing eifcctive amount in the rangefrom about .001 to 0.5 wt. percent of a pour depressant which comprisesessentially a condensation product of an acylated polystyrene and anamino compound, which condensation product has the following structurewherein R is a straight chain alkyl group of about 7 to 15 carbon atoms,wherein x is a number from 3 to 20, and wherein R is an amino group.

2. Composition as defined by claim 1 wherein said amino compound is aprimary aliphatic amine.

3. Composition as defined by claim 1 wherein said amino compoundcomprises an aromatic amine.

4. Composition as defined by claim 1 wherein said amino compoundcomprises dodecylamine.

5. Composition as defined by claim 4 wherein the condensation productcomprises about 1 mol of dodecylamine per mol of acyl groups.

References Cited in the file of this patent UNITED STATES PATENTS2,703,8 17 Serniuk Mar. 8, 1955

1. A PETROLEUM DISTILLATE FUEL COMPOSITION HAVING AN IMPROVED POUR ANDIMPROVED STABILITY AGAINST SEDIMENTATION WHICH COMPRISES ESSENTIALLY APETROLEUM DISTILLATE FUEL BOILING IN THE RANGE BETWEEN 250*F. AND ABOUT750* F. WHICH HAS BEEN IMPROVED WITH RESPECT TO POUR POINT BY THEINCORPORATION THEREIN OF A POUR DEPRESSING EFFECTIVE AMOUNT IN THE RANGEFROM ABOUT .001 TO 0.5 WT. PERCENT OF A POUR DEPRESSANT WHICH COMPRISESESSENTIALLY A CONDENSATION PRODUCT OF AN ACYLATED POLYSTYREENE AND ANAMINO COMPOUND, WHICH CONDENSATION PRODUCT HAS THE FOLLOWING STRUCTURE